Reason: For Day And Night

From space, astronauts see this line as a breathtaking, soft-edged arc where the blue of day bleeds into the black of night. Cities on one side are bustling. Cities just across the line are already asleep. To truly understand day and night, consider what wouldn’t happen.

That’s the name astronomers give to the moving boundary between day and night on any planet. On Earth, it sweeps across the globe constantly. When you watch a sunset, you aren’t watching the sun “go down.” You’re watching your piece of Earth rotate you past the terminator line and into the shadow. reason for day and night

Day and night have no separate cause. They are the same cause: a sphere in motion, a star at rest, and a universe that spins stories out of shadow and flame. From space, astronauts see this line as a